asciidoctorj-revealjs
· AsciidoctorJ RevealJs bundles the Asciidoctor Reveal.js RubyGem (asciidoctor-reveal.js) so it can be loaded into the JVM using JRuby.
Download JD-GUI to open JAR file and explore Java source code file (.class .java)
Click menu "File → Open File..." or just drag-and-drop the JAR file in the JD-GUI window asciidoctorj-revealjs-4.1.0.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.
